[patch] Assert when 'break' with no arguments

[Aleksandar Ristovski <aristovski@qnx.com>]

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Hello,

An issue exists where if 'break' command is issued while on a line that 
underwent inlining by the compiler gdb asserts with

Assertion `sal.pspace != NULL'

I narrowed down the issue to frame.c:find_frame_sal, combined with 
stack.c:set_last_displayed_sal and in the view of print_frame_info.

The fix proposed here would be to properly initialize 'sal' in 
find_frmae_sal. Additional check is performed in set_last_displayed_sal 
to make sure we do not set last_displayed_* vars and validate them if 
pspace is NULL as, clearly, the rest of the code expects it to be 
properly set.

I identified the same issue in 7.2, 7.3.1, 7.4 and HEAD. I have not 
checked earlier versions.

Test suite did not show regressions, and new test passes where it would 
fail without the patch.


ChangeLog:
2012-02-14  Aleksandar Ristovski  <aristovski@qnx.com>

        * frame.c (find_frame_sal): Initialise sal->pspace field from 
frame data.
        * stack.c (set_last_displayed_sal): Perform sanity check of the data
        passed in, in particular, validate that PSPACE is not NULL if 
requesting
        valid last_displayed_* data.


Test suite ChangeLOg:
2012-02-14  Aleksandar Ristovski  <aristovski@qnx.com>

     * gdb.base/break-inline.exp: New test.
     * gdb.base/break-inline.c: New test.


Attached are patch for the fix and tests.



Thank you,

Aleksandar Ristovski
QNX Software Systems

[-- Attachment #2: pspace-assert-201202141250.patch --]
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Index: gdb/frame.c
===================================================================
RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.304
diff -u -p -r1.304 frame.c
--- gdb/frame.c	4 Jan 2012 08:17:02 -0000	1.304
+++ gdb/frame.c	14 Feb 2012 16:35:12 -0000
@@ -2096,6 +2096,9 @@ find_frame_sal (struct frame_info *frame
 	   we can't do much better.  */
 	sal->pc = get_frame_pc (frame);
 
+      /* Set pspace with frame's pspace */
+      sal->pspace = get_frame_program_space (frame);
+
       return;
     }
 
Index: gdb/stack.c
===================================================================
RCS file: /cvs/src/src/gdb/stack.c,v
retrieving revision 1.247
diff -u -p -r1.247 stack.c
--- gdb/stack.c	7 Feb 2012 04:48:22 -0000	1.247
+++ gdb/stack.c	14 Feb 2012 16:35:12 -0000
@@ -904,11 +904,17 @@ set_last_displayed_sal (int valid, struc
 			CORE_ADDR addr, struct symtab *symtab,
 			int line)
 {
+  if (valid && pspace == NULL) {
+	warning(_("Trying to set NULL pspace."));
+  }
   last_displayed_sal_valid = valid;
   last_displayed_pspace = pspace;
   last_displayed_addr = addr;
   last_displayed_symtab = symtab;
   last_displayed_line = line;
+
+  if (valid && pspace == NULL)
+	last_displayed_sal_valid = 0;
 }
 
 /* Forget the last sal we displayed.  */

[-- Attachment #3: break-inline.exp --]
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#   Copyright 2012 Free
#   Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# This file was written by Rob Savoye. (rob@cygnus.com)



if { [prepare_for_testing break-inline.exp "break-inline" {} {debug nowarnings optimize=-O2}] } {
    return -1
}

gdb_test "start" "Temporary breakpoint.*"
gdb_test "next" "foo().*"


# Now test 'break' with no arguments.
gdb_test "break" ".*"


[-- Attachment #4: break-inline.c --]
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/* This testcase is part of GDB, the GNU debugger.

   Copyright 2012 Free Software
   Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <stdio.h>
static int g;
static inline void foo(void)
{
  g = 42;
  printf("%d\n", g);
}
int main(int argc, char *argv[])
{
  foo();
  return g;
}